Add button to add new FSP services to Files app.

chrome/app/chromeos_strings.grdp

Index: chrome/app/chromeos_strings.grdp
diff --git a/chrome/app/chromeos_strings.grdp b/chrome/app/chromeos_strings.grdp
index a939000bdb47c9b739545d9f58b5c2c1b1a97e86..a314f13089d2ce7f6c165f7f2cf60d80f478c1f2 100644
--- a/chrome/app/chromeos_strings.grdp
+++ b/chrome/app/chromeos_strings.grdp
@@ -244,6 +244,9 @@ Press any key to continue exploring.
   <message name="IDS_FILE_BROWSER_CLOSE_VOLUME_BUTTON_LABEL" desc="Title of the action for closing either an archive volume or a volume provided by an extension.">
     Close
   </message>
+  <message name="IDS_FILE_BROWSER_ADD_NEW_SERVICES_BUTTON_LABEL" desc="Title of the button in the left nav to add new services (file systems) to Files app.">
+    Add new services
+  </message>
   <message name="IDS_FILE_BROWSER_ACTION_VIEW" desc="Title of the action to view (no edit) a file.">
     View
   </message>
@@ -678,6 +681,9 @@ Press any key to continue exploring.
   <message name="IDS_FILE_BROWSER_SUGGEST_DIALOG_TITLE" desc="Title of the suggest app dialog, which shows the list of the apps which supports the selected file.">
     Select an app to open this file
   </message>
+  <message name="IDS_FILE_BROWSER_SUGGEST_DIALOG_FOR_PROVIDERS_TITLE" desc="Title of the suggest app dialog, which shows the list of the apps that can be added to the left nav of Files app.">
+    Available services
+  </message>
   <message name="IDS_FILE_BROWSER_SUGGEST_DIALOG_LINK_TO_WEBSTORE" desc="Text of the link to the app list on Chrome Webstore, which shows the more apps than in the suggest app dialog.">
     See more...
   </message>